Fastest Possible Switching in Magnetite Measured

Central to the operation of computers is the ability for a material to switch from a conducting to non-conducting state, and back. The faster this switching can happen, the faster a transistor based on this material can operate. Researchers at the SLAC National Accelerator Laboratory have recently determined the fastest possible switching speed of magnetite, a naturally magnetic material.

To make the needed measurements, the researchers used the Linac Coherent Light Source (LCLS) X-ray laser to pump enough energy into the magnetite sample to change its electronic structure and then probe it with a second pulse. The first pulse was from a visible light laser and successfully fragmented the electronic state of the atoms into island, which the second X-ray laser pulse was able to detect. These islands can be conducting or non-conducting, so by controlling their placement, it should be possible to create electrical pathways within the material.

The researchers clocked the switching at only a trillionth of second, or one picosecond, which is thousands of times faster than the materials used in modern transistors. Unfortunately the magnetite sample had to be cooled to -190 ºC, which would be too cold to use in desktops. The researchers are now looking at other materials though that may have comparable switching speeds at room temperature.